Transmission should not be a problem. Allisons auto's (old style AT545 or similar) or various manuals will bolt right up. Lots of old manual transmissions at local wrecking yards. I saw that aluminum block on ebay also. You might want to buy a "parts" 471 to get all the components you will need at a reasonable cost. Rebuild kits will have liners, pistons and that, but lots of small parts will be required, and buying them from a parts store could get expensive.